Methods and apparatuses for formation of topographical microstructures and patterning of textured surfaces using photopolymerization

Abstract

Disclosed are systems, methods, and apparatuses for fabricating topographical microdevices and textured surfaces with arbitrary geometries using frontal photopolymerization. The method can include disposing a volume of a liquid resin on a transparent substrate, projecting a patterned light on the liquid resin or through the transparent substrate, varying the patterned light in order to focus a projection focal plane of the patterned light on an interface between the transparent substrate and the liquid resin in order to initiate polymerization of the photocurable monomer at said interface, and laterally and temporally modulating an effective exposure energy dose of the patterned light relative to a total depth of the liquid resin, wherein the exposure energy dose is a product of light exposure time and exposure intensity for respective of the different portions of the liquid resin.

What is claimed is: 
     
         1 . A method for fabricating a polymeric device or a polymeric surface with arbitrary geometries and topographical textures, the method comprising:
 disposing a volume of a liquid resin onto a first surface of a transparent substrate, the liquid resin comprising a photocurable monomer;   projecting a patterned light onto a second surface of the transparent substrate, the second surface being opposite the first surface, wherein the transparent substrate is dimensioned and configured such that at least a portion of the patterned light travels through the transparent substrate from the second side to the first side;   varying one or both of a light exposure time or a light intensity of the patterned light to focus a projection focal plane of the patterned light on an interface between the first surface of the transparent substrate and the liquid resin disposed thereon to initiate polymerization of the photocurable monomer at said interface; and   varying, for respective of the different portions of the liquid resin, at least one of the light exposure time or the light intensity of the patterned light to modulate an effective exposure energy dose of the patterned light relative to a total depth of the liquid resin on the first surface of the transparent substrate, wherein the effective exposure energy dose is a product of at least the light exposure time and the light intensity.   
     
     
         2 . The method of  claim 1 , wherein the liquid resin comprises one or more of: a photoinitiator, a photoabsorber, an inhibitor, a dye, or nanoparticles. 
     
     
         3 . The method of  claim 1 , further comprising:
 controlling vertical polymerization by varying at least one of a resin formulation or the effective exposure energy dose.   
     
     
         4 . The method of  claim 1 , wherein a characteristic absorption length of the liquid resin is inversely correlated with an absorption constant of the liquid resin. 
     
     
         5 . The method of  claim 1 , further comprising:
 controlling a minimum exposure energy dose to control polymerization of the liquid resin.   
     
     
         6 . The method of  claim 1 , wherein the liquid resin comprises one or more of: one or more photocurable monomers, one or more photoinitiators, one or more absorbers, one or more dyes, one or more functional fillers, or one or more inhibitors. 
     
     
         7 . The method of  claim 1 , wherein the transparent substrate comprises one or more of: a glass, a microscope slide, a cyclic olefin copolymer film, or a polyethylene terephthalate film. 
     
     
         8 . The method of  claim 1 , further comprising:
 functionalizing the first surface of the transparent substrate by coating the first surface of the transparent substrate with a functional material to facilitate adhesion or removal of the polymeric device or polymeric surface from the first surface of the transparent substrate.   
     
     
         9 . The method of  claim 1 , further comprising:
 functionalizing the second surface of the transparent substrate by coating the second surface of the transparent substrate with one or more of: an anti-reflective coating, a light filter coating, a light polarization coating, a stencil, a mask, a wavelength filtering coating, or a patterning coating.   
     
     
         10 . The method of  claim 1 , wherein the spatial light modulator comprises one or more of: a digital light projector (DLP) configured to project said patterned light, a liquid crystal display device, or a liquid crystal on silicon device. 
     
     
         11 . The method of  claim 1 , further comprising:
 tilting, vertically translating, or laterally translating the transparent substrate to modulate the effective exposure energy dose of the patterned light relative to the total depth of the liquid resin or vary a position or an angle of the projection focal plane with respect to one of the first or second surface of the transparent substrate.   
     
     
         12 . The method of  claim 1 , further comprising:
 causing the volume of the liquid resin to be mixed, stirred, vibrated, oscillated, agitated mechanically, or kept in a state of continuous flow.   
     
     
         13 . A method for fabricating a multi-material polymeric device or a multi-material polymeric surface, the method comprising:
 disposing a volume of a first photocurable monomer onto a surface of a substrate;   projecting a patterned light into one or more portions of the volume of the first photocurable monomer;   modulating an effective exposure energy dose of the patterned light within the one or more portions of the first photocurable monomer to cause the one or more portions of the volume of the first photocurable monomer to form one or more first photocured structures, wherein the exposure energy dose is a product of at least a light exposure time and a light intensity of respective portions of the patterned light that reach respective of the one or more portions of the first photocurable monomer;   disposing a volume of a second photocurable monomer onto the surface of the substrate and/or onto at least a portion of the one or more photocured structures;   projecting the patterned light into one or more portions of the volume of the second photocurable monomer; and   modulating the effective exposure energy dose of the patterned light within the one or more portions of the second photocurable monomer to cause the one or more portions of the volume of the second photocurable monomer to form one or more second photocured structures.   
     
     
         14 . The method of  claim 13 , further comprising:
 in an instance in which only a portion of the volume of the first photocurable monomer forms the one or more first photocured structures, removing a remaining portion of the first photocurable monomer, the remaining portion of the first photocurable monomer comprising an uncured portion of the volume of the first photocurable monomer.   
     
     
         15 . The method of  claim 14 , further comprising:
 in an instance in which only a portion of the volume of the second photocurable monomer forms the one or more second photocured structures, removing a remaining portion of the second photocurable monomer, the remaining portion of the second photocurable monomer comprising an uncured portion of the volume of the second photocurable monomer.   
     
     
         16 . The method of  claim 13 , wherein the first photocurable monomer is different from the second photocurable monomer. 
     
     
         17 . The method of  claim 16 , wherein one or both of the first photocurable monomer or the second photocurable monomer comprises one or more of: a photoinitiator, a photoabsorber, an inhibitor, a dye, or nanoparticles. 
     
     
         18 . A continuous or semi-continuous method for fabricating a polymeric device or a polymeric surface, the method comprising:
 moving a flexible substrate along a path between a dispensing roll and a receiving roll;   disposing one or more volumes of a photocurable monomer onto one or more portions of the flexible substrates;   projecting a patterned light into the one or more volumes of the photocurable monomer at one or more points along said path between the dispensing roll and the receiving roll; and   modulating an effective exposure energy dose of the patterned light within the one or more volumes of the photocurable monomer to cause the one or more volumes of the photocurable monomer to form one or more photocured structures, wherein the exposure energy dose is a product of at least a light exposure time and a light intensity for the patterned light received at respective volumes of the one or more volumes of the photocurable monomer.   
     
     
         19 . The method of  claim 18 , further comprising:
 projecting the patterned light in multiple sequential exposures, wherein an inter-exposure routine is performed between the sequential exposures of projected patterned light,   wherein the inter-exposure routine comprises mixing or stirring the liquid resin, removing the liquid resin, disposing a solvent, removing a solvent, replacing the liquid resin with a liquid resin with a same or different composition, and/or moving the spatial light modulator.   
     
     
         20 . The method of  claim 18 , wherein one or both of the first photocurable monomer or the second photocurable monomer comprises one or more of: a photoinitiator, a photoabsorber, an inhibitor, a dye, or nanoparticles.